New MIS 19 EPICA Dome C high resolution deuterium data: hints for a problematic preservation of climate variability at sub-millennial scale in the “oldest ice”

• Published in: Earth and Planetary Science Letters
• Main Authors: Pol K., Masson Delmotte V., Johnsen S., Bigler M., Cattani O., Durand G., Falourd S., Jouzel J., Minster B., Parrenin F., Ritz C., Steen Larsen H. C., STENNI, Barbara
• Other Authors: Pol, K., Masson Delmotte, V., Johnsen, S., Bigler, M., Cattani, O., Durand, G., Falourd, S., Jouzel, J., Minster, B., Parrenin, F., Ritz, C., Steen Larsen, H. C., Stenni, Barbara
• Format: Article in Journal/Newspaper
• Language: English
• Published: 2010
• Subjects: Antarctica; Ice core; Isotopic diffusion; Water stable isotope; Antarc*; EPICA; ice core
• Online Access: http://hdl.handle.net/10278/42699; https://doi.org/10.1016/j.epsl.2010.07.030

Marine Isotope Stage 19 (MIS 19) is the oldest interglacial period archived in the EPICA Dome C ice core (~780 ky BP) and the closest “orbital analogue” to the Holocene — albeit with a different obliquity amplitude and phase with precession. New detailed deuterium measurements have been conducted with a depth resolution of 11 cm (corresponding time resolution of ~130 years). They confirm our earlier low resolution profile (55 cm), showing a relatively smooth shape over the MIS 20 to MIS 18 time period with a lack of submillennial climate variability, first thought to be due to this low resolution. The MIS 19 high resolution profile actually reveals a strong isotopic diffusion process leading to a diffusion length of at least ~40 cm erasing sub-millennial climate variability. We suggest that this diffusion is caused by water-veins associated with large ice crystals at temperatures above −10 °C, temperature conditions in which the MIS 19 ice has spent more than 200 ky. This result has implications for the selection of the future “oldest ice” drilling site.